This document discusses different types and components of computers. It describes six types of computers classified based on their capacity and performance: super computers, mainframes, mini computers, personal computers, laptops, and palmtop computers. The major components of a personal computer are then outlined, including the system unit, input devices, output devices, and peripherals. Details are provided on the central processing unit and its components. Common input devices like keyboards and mice and output devices like monitors and printers are also listed.

1. By: Azar Abid Salih
MSc of Computer Science
D.P.U / Administrative Technical
College
IT Dept. / First Class
Information Technology
Fundamentals
Lecture 2
124 October 2017

2. • Types of Computer
• Parts of a Computer
• The Central Processing Unit ( CPU )
• Input Devices
• Output Devices
Outlines:
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3. Mainframes
Types of Computer
Super Computers
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4. PC
Types of Computer
Mini Computers
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5. Palmtop Computers
Types of Computer
Laptop Computers
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6. Types of Computer
Network Computers
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7. Computers are classified according to
their capacity and performance:
1. Super Computers:
Are high-capacity computers that cost
millions of dollars very expensive, very
high speed and are often used in:
- Weather forecasting.
- Oil exploration.
- Aircraft design.
- NASA.
Types of Computer:
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8. 2. Mainframes:
Room-sized, expensive, high speed,
very powerful, large storage capacities
and occupy special air-conditioned rooms.
They are used in:
- Banks.
- Government departments.
- Large organizations.
Types of Computer: (cont.)
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9. 3. Mini Computers:
Do the same jobs as a mainframe,
but on a smaller scale.
They are used by medium-sized
computers for specific purposes, less cost,
such as accounting, where personal
computers would be inadequate.
Types of Computer: (cont.)
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10. 4. Personal Computers ( PC ):
Are small enough to fit on top of a
desk in offices and at home and are
designed for an individual user.
In 1981, IBM produced its first
personal computer, known as the IBM
PC.
Types of Computer: (cont.)
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11. 5. Laptop Computers:
Its small, briefcase-sized and
portable. It has a small screen and a
small keyboard.
Types of Computer: (cont.)
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12. 6. Palmtop Computers:
It is a hand-held computer, which is called
a Notepad. It has a small screen and keyboard.
It performs some special functions and is
considered to be cheap.
Personal Digital Assistants (PDA) are small
pen controlled, handheld computers.
Instead of pecking at a tiny keyboard,
you can use a special pen to write out
commands on the computer screen.
PADs can be used to send and receive
faxes and E-mail, to write memos.
Types of Computer: (cont.)
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13. 7. Network Computers:
A large PC-type computer called a
Server is connected to smaller PCs called
Clients or Terminals.
Types of Computer: (cont.)
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14. The major components of a PC are:
1. System Unit:
This unit contains the following
parts:
 The Motherboard or System Board is
the main circuit board in the system
unit.
Parts of a Computer:
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15.  Memory is the part of the computer
that temporarily stores applications,
documents, and system operating
information.
 A Power Supply changes the normal
household electricity into electricity
that a computer can use.
Parts of a Computer: (cont.)
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16.  A Port is a socket on the outside of the
system unit that is connected to an
expansion board on the inside of the
system unit.
There are three types of ports:
 A Parallel Port.
 A Serial Port.
 A Small Computer System Interface
[SCSI] Port.
 USB Port.
Parts of a Computer: (cont.)
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17.  Expansion Slots are sockets on the
motherboard into which you can plug
the expansion board. Such as Graphic
Adapter, Sound Card, Modem Card.
 Device Controllers are circuit boards that
allow your CPU to work with the
computer’s various peripheral devices
such as disk drivers, monitor, keyboard,
mouse and printer.
Parts of a Computer: (cont.)
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18.  A Desk Drive is a device that holds data,
and reads data from and writes data to
a desk.
 The System Clock controls the time
performing all the operations within a
computer. Processing speeds are
expressed in megahertz (MHz).
1 MHz = 1 million cycle per second
Parts of a Computer: (cont.)
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19.  Light Emitting Diodes (LED) are small
light sources that are used to indicate
that the computer is switched on, and
to indicate the level of activity.
Parts of a Computer: (cont.)
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20. 2. Input Devices:
This group consists of devices that
allow people to put data into the
computer in a form that the computer
can use, such as keyboard and mouse.
Parts of a Computer: (cont.)
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21. 3. Output Devices:
This group consists of devices that
translate the information processed by
the computer into a form that humans
can understand, such as a monitor which
displays the results.
Parts of a Computer: (cont.)
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22. 4. Peripherals:
Any piece of hardware that is
connected to a computer, such as a
printers, scanners and modem.
These are used to perform special
input and output tasks.
Parts of a Computer: (cont.)
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23. Every PC’s system unit contains at
least one chip called Microprocessor or
CPU, attached on the Motherboard.
The CPU:
 It is the brain of computer.
 It interprets and executes the instruction
contained in software program.
 It determines how fast your computer
will run.
The Central Processing Unit: (CPU)
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24. CPUs have three basic parts:
1. Arithmetic and Logic Unit (ALU):
Performs arithmetic operations such
as (A= 10 + 5 / B) and logical operations
such as (IF AV >= 50 Print [“Pass”]) and
controls the speed of those operations.
The Central Processing Unit: (CPU)
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25. 2. Control Unit (CU):
Tell the rest of the computer system
how to carry out a program’s
instructions.
It directs the movement of
electronic signals between main
memory and the arithmetic unit, input
and output devices.
The Central Processing Unit: (CPU)
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26. 3. Registers or Immediate Access
Memory (Cash Memory):
Where the data used by the ALU
and the program instructions, which are
used by the CU, are stored.
The Central Processing Unit: (CPU)
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27. Input devices allow you to input data
or information to the computer.
 Keyboard.
 Mouse.
 Trackball.
 Touch Pad.
 Light Pen.
 Scanners.
Input Devices:
Bar Code Reader.
Joystick.
Magnetic Strip.
Microphone.
Digital Camera.
Video Camera.
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28. Input Devices
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29. The term Output refers to processed data or
information. It typically takes the form of text,
graphics, photos, audio, and/or video.
Output devices are any hardware used to
provide or to create output.
 Video Display Units (VDU).
 Monitors.
 Printers.
 Plotters.
 Speakers.
 Projectors.
Output Devices:
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30. Output Devices
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31. The END…
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